acting irs commissioner steven miller signed some of the responses to lawmakers. he's expected to face some tough questions when he testifies before congress on friday. >> this is a big deal. we're not going to let it rest. >> reporter: house republicans are introducing a bill that would make it a crime for irs workers to discriminate against groups for their political views. and more are questioning who at the white house knew about this and when. the president said he learned of it all on friday but jay carney, the white house spokesman, said yesterday that the white house counsel learned about an investigation into this matter the week of april 22nd. >> susan mcginnis in washington. thank you, susan. >>> republican lawmakers are moving forward with their investigation of last year's attack on the u.s. mission in benghazi, libya. the obama administration continues to deny allegations of a coverup. the white house insists there was no effort to change the so-called talking points to downplay the possibility of terrorism. president obama says the investigation is